The invention relates to rolling mills in general, and more particularly to improvements in methods of ascertaining the magnitude of forces which act upon the rolls of a rolling mill while the mill is in actual use. The invention also relates to improvements in rolls which can be used in rolling mills and to instruments which can be used for carrying out the measurements.
It is often desirable and/or necessary to ascertain the magnitude of forces which act upon the rolls of a rolling mill when the mill is in actual use. Such ascertainment of forces is often important in mills which operate with cylindrical rolls as well as in mills which employ grooved rolls. The magnitude of forces acting upon the rolls in actual use of the mills is indicative of the extent of deformation of the rolls. For example, reliable monitoring of the magnitude of forces renders it possible to forestall or detect in time potential or actual breaks as a result of overstressing of the rolls. Furthermore, it is possible to properly regulate tensile stresses which are transmitted between discrete roll stands by the material which is being subjected to a rolling operation; this can be achieved by appropriate selection of the stand RPM and/or appropriate adjustment of the stands. Still further, a monitoring of the magnitude of forces which act upon the rolls renders it possible to properly evaluate and control the rolling operation as to reproducibility as well as to improve the economy of operation and prolong the useful life of the rolls and of the entire mill.
In accordance with heretofore known proposals, the magnitude of forces which act upon the rolls in a rolling mill is determined indirectly by measuring the magnitude of forces which act upon the bearings for the rolls. Such measurement is not always reliable because it takes place at a locus which is remote from the region of maximum deformation of the rolls and from the point or points of application of the force. Moreover, manufacturing tolerances contribute to distortion of the results of such measurement at the bearings. Still further the measurement takes place with a certain delay following the application of forces to the rolls. Last but not least, hysteresis can adversely influence the accuracy of measurements at the bearings. Heretofore known measurements must be carried out by resorting to bulky, complex and expensive apparatus which are prone to malfunction.